Wood rechipper



` Feb. 17, Al BERGMAN 2,873,923

. woon RECHIPPER Filed July 16, 1956 l INVENTOR. l-f 2' phuz Bergman Y B77M a? HHN.

United States Patent O WOOD RECHIPPER Arthur Bergman, Longview, Wash.,assiguor to Columbia Veneer Company, Seattle, Wash., a corporation ofWashington Application July 16, 1956, Serial No. 598,041 1 Claim. (Cl.241--280) This invention relates to a rechipper for reducing large woodchips to chips of smaller dimensions.

When making paper pulp, wood first is reduced to the form of chips whichthen are digested with the selected chemicals until they are convertedto pulp. In this sequence, it is critical that the chips be of uniformdimensions. If they are too large, they do not digest completely in theallotted cooking period with the result that a non-uniform pulp, andhence a non-uniform paper product, is obtained.

Accordingly it is common practice to screen the wood chips produced byany of the conventional wood chippers for the removal of oversizedchips. This results in the separation of from 3% to 5% of chipsmeasuring from two to six inches in length which must be reduced furtherif they are to be used as a source of pulp. Their reduction is difcultof accomplishment, however, since if they are merely rerun through theoriginal chipper, or passed through other chppers of conventionaldesign, they pass between the knives or at best are split lengthwise sothat the desired transverse reduction is not obtained. As a consequence,it is common practice to burn the oversize chips which accordingly arelost as a source of paper pulp.

It is the general object of the present invention to provide a rechipperwhich eiectively and economically reduces in size the oversize chipsproduced in the foregoing manner so that a chipped product is obtainedwhich may be digested satisfactorily in the manufacture of paper pulp.

The manner in which the foregoing and other objects of the presentinvention are accomplished Will be apparent from the accompanyingspecification and claim considered together with the drawings, wherein:

Fig. 1 is a view in side elevation, partly in section, illustrating theconstruction of the herein described Wood ICC ` particular reference tothe drawings;

rechipper, the sectional portion of the cutter head being as viewedtoward the right in Fig. 2 from the longitudinal center line of thecutter head;

Fig. 2 is a fragmentary plan view illustrating the construction of thecutter head and anvil incorporated in the Wood rechipper of Fig. l; and

Fig. 3 is a view in side elevation of the cutter head included in therechipper illustrated in Figs. l and 2.

Broadly stated the Wood rechipper of mylinvention comprises acylindrical head, mounting means for rotatably mounting the head, andcoupling means for coupling the head to a source of power. A pluralityof knives having outwardly arcuate cutting edges are mounted obliquelyon the cutter head, preferably in a V-shaped configuration. An anvil ismounted opposite the cutter head for cooperation therewith. Feedingmeans also are provided for feeding chips to the knives in a verticaldirection. When this is done, the unique construction of the cutter headand knives results in upending the chips, and in guiding them toward thecentral portion of the head, where they are cut transversely intolengths suitable for pulping.

.T he herein described wood rechipper includes a cylindrical cutter head10 keyed to a shaft 12 which is mounted for rotation in bearings 14.Shaft 12 is coupled by means of pulley 16 or other means to a suitablesource of power, for example an electric motor operating at the desiredrate.

A plurality of knives 20 are mounted obliquely on the cutter head. Theknives preferably are shorter than the cutterhead is long and arearranged in pairs in a V -pattern as is illustrated particularly in Fig.2. lThe knife shown lin Fig. l terminates at its right-hand end on thelongitudinal center line of the head 10, and at its lefthand end at oneend of the head. Thus, with the head rotating in the direction of thearrow in Fig. l, the apex of the V pattern of the pair of knives trailsthe lateral ends thereof. The knife edges have a contour which isoutwardly arcuate and accordingly a pronounced crown is present on them.

Cooperating with the knives is an anvil 22 having a slot 24therethrough. The working face of the anvil is angular and includes afirst or guiding section 26 and a rectilinear working section 28disposed obliquely thereto. The latter is aligned substantially with thepath of travel of the knives.

Means are provided for adjusting the anvil toward and away from thecutter head assembly. In the illustrated form of the invention, theanvil is bolted to frame members 32, 34 by means of a bolt 30 whichpenetrates slot 24 in the anvil. A second bolt 36 is threaded into aframe member and abuts the back surface of the anvil. Accordingly, uponloosening bolt 30, the anvil may be moved to the desired position.Thereafter bolt 30 may be tightened, clamping the anvil in place. Bolt36 then may be advanced until it is in abutment with the anvil, Where itstabilizes it and backs it up against the thrust of the cuttingoperation.

Means also are present for feeding material to the cutting assembly.Such means comprises a vertical hopper dened in part by a vertical plate38, an inclined plate 40 and sidewalls 42, 44. The surface of plate 40is substantially aligned with guiding surface 26 of anvil 22 so thatchips pass smoothly down the hopper against the cutter head.

In operation, anvil 22 is adjusted so that it is in effective Workingrelationship to knives 20. Cutter head 10 then is set in motion at thedesired rotational rate and wood pieces, for example oversize chipsresulting from the action of a chipper on waste wood veneer or other rawmaterial, are introduced into the hopper. The chips pass in asubstantially vertical direction down on to the cutter head where theaction of the knives first up-ends them and then cuts them transverselyso that short pieces are formed.

In addition, the oblique setting of the knives works the chips towardthe central portion of the cutter head so that they are not passedbetween the ends of the head and the sidewalls of the apparatus. As aconsequence the chips are reduced effectively to smaller chips suitablefor cooking in a Wood pulping operation in the usual manner.

It is to be understood that the form of my invention herewith shown anddescribed is to be taken as a preferred example of the same and thatvarious changes in the shape, size and arrangement of the parts may beresorted to without departing from the spirit of my invention or thescope of the subjoined claim.

Having thus described my invention, I claim:

A wood rechipper comprising a cylindrical head, head mounting means forrotatably mounting the head, coupling means for coupling the head to asource of power, anvil means stationed adjacent the head a spaceddistance therefrom and having a rectilinear Working section arrangedparallel to and above the horizontal axis of the head, a plurality ofknives mounted on the head in a transverse V shape with the apex thereoftrailing the side edges in the direction of rotation of the head, thecutting edges of the knives being defined by uninterrupted planesurfaces` and being contoured arcuately for cooperation with therectilinear working surface of the anvil during rotation of the head, a'hopper positioned above the knives and having a wall thereof inclineddownwardly toward the anvil means, and an upper guiding section on theanvil means having a surface arranged obliquely with respect to thelower working section and disposed substantially in the plane of theadjacent hopper wall.

AReferences Cited in the tile of this patent UNITED STATES PATENTSForbes Aug. 26, 1879 Carter et al. Oct. 15, 1889 Milts et al. July 3,1928 Pendleton Jan. 15, 1929 Becker July 10, 1951 FOREIGN PATENTS SwedenFeb. 14, 1903 Germany Apr. 5, 1886 Norway Jan. 18, 1926 Sweden Apr. 20,1926

